package org.pretty.common.utils;

import java.security.SecureRandom;

import javax.crypto.Cipher;
import javax.crypto.SecretKey;
import javax.crypto.SecretKeyFactory;
import javax.crypto.spec.DESKeySpec;

/**
 * 
 * @author lazyp
 *
 */
public final class DESUtils {
    /**
     * Description 根据键值进行加密
     * 
     * @param data
     * @param key
     *            加密键byte数组
     * @return
     * @throws Exception
     */
    public static byte[] encrypt(byte[] data, byte[] key) throws Exception {
        // 生成一个可信任的随机数源

        SecureRandom sr = new SecureRandom();

        // 从原始密钥数据创建DESKeySpec对象

        DESKeySpec dks = new DESKeySpec(key);

        // 创建一个密钥工厂，然后用它把DESKeySpec转换成SecretKey对象

        SecretKeyFactory keyFactory = SecretKeyFactory.getInstance("DES");
        SecretKey securekey = keyFactory.generateSecret(dks);

        // Cipher对象实际完成加密操作

        Cipher cipher = Cipher.getInstance("DES");

        // 用密钥初始化Cipher对象

        cipher.init(Cipher.ENCRYPT_MODE, securekey, sr);

        return cipher.doFinal(data);
    }

    /**
     * Description 根据键值进行解密
     * 
     * @param data
     * @param key
     *            加密键byte数组
     * @return
     * @throws Exception
     */
    public static byte[] decrypt(byte[] data, byte[] key) throws Exception {
        // 生成一个可信任的随机数源

        SecureRandom sr = new SecureRandom();

        // 从原始密钥数据创建DESKeySpec对象

        DESKeySpec dks = new DESKeySpec(key);

        // 创建一个密钥工厂，然后用它把DESKeySpec转换成SecretKey对象

        SecretKeyFactory keyFactory = SecretKeyFactory.getInstance("DES");
        SecretKey securekey = keyFactory.generateSecret(dks);

        // Cipher对象实际完成解密操作

        Cipher cipher = Cipher.getInstance("DES");

        // 用密钥初始化Cipher对象

        cipher.init(Cipher.DECRYPT_MODE, securekey, sr);

        return cipher.doFinal(data);
    }
}
